1.
-GROWTH,
FATTENING ANDOUALITY
OF LAMB AND KID CARCASSESOverall growth of the lamb: its characteristics and rules
M. PRUD’HON
Station de
Plcysiologie animale, 7.A!.7!.!.,
E.N.S.A.place Viala, 3 ¢ 0 6o Montpelliev
CedexA
descriptive study
of theprenatal
andpost-natal growth
of the lamb and the methods used to determine its characteristics was made.Unpublished
data on the dissection of 80 lambsbelonging to different genotypes (Romanov, Merino,
Romanov XMerino, Berrichon,
Bcrrichon XMerino) slaughtered
at 25, 50, 100 andi jo
days
of age were used.Breed
comparisons
were done at similardegrees
ofmaturity (slaughter weight /adult weight)
The results show
large
breed differences in thegrowth
of various organs and fatdeposits
butnot in the
proportions
of muscles and bones. These differences decreased whendegree
of matu-rity
reached 0.25 to 0.60.The allometric coefficient of
empty liveweight
or total mass of similar tissue was also used to characterize thegrowth
of different organs and tissues. The usual rules for differentialgrowth
were verified for each
genotype studied; however,
there are some differences in themagnitude
of the allometric coefficient in these 5
genotypes. Roughly,
thismagnitude
varied less in the muscle tissue from onegenotype
to another.However,
there are differences in muscle massdistribution,
i.e. at the samedegree
ofmaturity,
the Romanov and the Merino had more shoulder muscle and lessleg
muscle than the Berrichon.The
prerequisites
for aninventory
ofgrowth
characteristics and anatomicalcomposition
of the main French
sheep
breeds arc outlined. The utilisation ofsimple
estimators forpredict- ing growth
issuggested.
General aspects of the development and growth
of muscle and adipose tissues : characteristics in sheep
A. VEZINHET
J.
NOUGUES P. VIGNERONStation de
Physiologie anima.le, 7.!V./t’.!.,
E.N.S.A.,placc l,’iala, 34 o6o -Ilontpellier
CedcxThe aim in meat
production
is to increase the muscle mass(which
is theprotein fraction)
in the carcass and obtain an
optimal
amount offatty
tissue. Tosatisfy
theseobjectives,
it isnecessary to have a better
knowledge
of the xnechanismsgoverning
muscle andadipose develop-
ment. To do
